University study identifies campylobacter preventative measures

A three-year study into the factors influencing campylobacter in chicken broiler houses has been published by the University of Bristol’s School of Veterinary Sciences.

Taking samples from between 2013 and 2016, the research outlined how reductions in campylobacter levels could be made through cost-effective changes in farming best-practice.

Bird gender, age at slaughter, shed size and the shed frame construction material were significant predictors of levels of campylobacter.

Campylobacter is the most common cause of food poisoning in the UK and the bacteria is responsible for more than 280,000 cases of food poisoning each year. It is estimated to cost the UK economy approximately £900 million, and about four in five cases of campylobacter poisoning in the UK come from contaminated poultry.

Recent figures provided by Public Health England, Public Health Wales, Health Protection Scotland and the Public Health Agency in Northern Ireland revealed a 17% decline in the number of laboratory reports of human cases of campylobacter in 2016.

Retail levels of campylobacter in chicken have also continued to decline. According to the FSA, the results for the first five months of its third retail survey, from August to December 2016, showed that, overall, 7% of chickens tested positive for campylobacter within the highest band of contamination.

Findings in the University of Bristol’s research included houses containing exclusively female birds had lower campylobacter levels compared with sheds containing male gender birds. Mixed gender sheds also tended to have significantly lower counts.

The report showed that if prebiotics were fed to birds, the mean log10 count was increased by 1.400 (p < 0.001) and that freezing chickens and chicken meat could lower levels of campylobacter.

On a hygiene level, the presence of darkling beetles in the litter was significantly correlated with elevated campylobacter numbers, while farmers that excluded their dogs from the houses had significantly decreased numbers of campylobacter species in the litter. Also, increasing the frequency of dipping boots in disinfectant was significantly correlated with lowered levels of campylobacter.

Mike Hutchison, who managed the study at the University of Bristol School of Veterinary Sciences, said: “An initial model to predict numbers of campylobacter on broiler carcase neck skins after chilling determined that more than three times the variance observed in slaughterhouses was explained by on-farm factors. Therefore, it is likely that farm-based interventions would be more financially and practically effective in lowering flock colonisations by campylobacter.”

Clare Taylor, senior lecturer in medical microbiology at Edinburgh Napier University and general secretary of the Society for Applied Microbiology (SfAM) added: “In recent years we have seen reports that campylobacters are present in around 75% of supermarket chickens. And with an increasing focus on the reduction of the use of antibiotics in animal husbandry, it is clear that hygienic practices in poultry processing can play a key role in reducing contamination. The authors of this study have identified a number of key interventions that could reduce campylobacter contamination and improve food safety.”